Children and young adults with spinal cord injury (SCI) commonly show sleep-disordered breathing (SDB), which is associated with increased morbidity and mortality, with an incidence conservatively reported at over 30%. Current treatments for SDB have high non-compliance due to associated discomfort or lack of efficacy. The most common intervention, continuous positive airway pressure, poses special problems with children and young adolescents, since the necessary masks distort developing facial bone structure over time, often forcing surgical reconstruction, and are difficult to fit as the child grows. Passive limb movement, the rhythmic movement of extremities without voluntary effort, increases ventilation during sleep in subjects with intact spinal cords; the impact of this intervention in complete thoracic SCI (paraplegic) patients lacking sensory information from the lower limbs is unknown. We hypothesize that passive limb movement (PLM) in these SCI patients with intact spinal cords above the thoracic cord region will decrease SDB [decrease the Apnea- Hypopnea Index (AHI)] for both obstructive and central apnea events, improve ventilation and oxygenation, and do so without arousing subjects during the night.. Using a one-group, quasi-experimental, pre- and post- test design, we will perform overnight polysomnography on 26 pediatric and young adults with complete thoracic spinal cord injury (ASIA A paraplegia, age 12-25 years), earlier screened to show SDB, who will be randomized to undergo passive limb (hand) movement either during the first or last half of the night during overnight polysomnography. The specific aims for this study are to: 1) Determine whether PLM therapy in pediatric and young adults with complete thoracic SCI (complete paraplegia) with SDB will improve SDB (as indicated by apnea-hyperpnoea index), ventilation (end-tidal carbon dioxide), and oxygen saturation; and 2) Compare number of arousals in pediatric and young adults with complete thoracic SCI during baseline sleep and during sleep when they are receiving PLM therapy. The objective of this study is to determine whether a novel treatment, passive limb movement, will improve ventilation in complete thoracic SCI adolescents and young adults with SDB, and do so with minimal disturbance to sleep. If passive limb movement improves ventilation and is tolerable to SCI patients, the intervention will provide an inexpensive, non-invasive therapy that could change clinical practice and significantly improve quality of life and outcomes in this high risk patient population.